Can Nanoparticles Help Fight Hunger? | Christy L. Haynes | TED

27,744 views ・ 2024-02-27

TED


Please double-click on the English subtitles below to play the video.

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Imagine you're a farmer
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and you've planted enough crops to feed your family for the coming year.
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The weather is surprisingly good at the beginning of the growing season,
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but after those seeds are in the ground
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and the stalks start to peek up from the soil,
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a disease that you cannot see cuts your expected yield in half.
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You think to yourself,
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"What will my family eat?"
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In the coming year,
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perhaps you'll fumigate your soil, maybe you'll add extra fertilizer.
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Maybe you'll apply a fungicide or a pesticide
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hoping to decrease crop loss.
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You know that these traditional technologies work,
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but you also know they have some negative implications for our ecosystem.
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This, of course, is not an imaginary scenario.
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We could feed every person on this planet if we didn't lose so much to disease,
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pest and poor soil conditions.
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It's estimated that we lose between 20 and 40 percent of crop productivity
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due to preventable disease and pest attack,
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and climate change is only making this worse.
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I stand here in front of you,
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a very unlikely person to help solve an agricultural crisis.
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I'm a chemistry professor who studies nanoparticles in sterile laboratories,
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I grew up in the desert,
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and I don't even keep houseplants, much less crops, alive.
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But I know that some of the best solutions to big problems
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come when folks from different or even opposing fields
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bring some of their simplest concepts together.
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And that is exactly what I think is possible here.
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As I tell you that nanoparticles may be a critical part
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of the solution to our global food crisis.
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Let me tell you why I'm so intent on using nanoscience to fight hunger.
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We all have the issues that touch us deepest,
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and for me, it has always been hunger.
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I find it intolerable that there are hungry people
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on this life-giving planet of ours.
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I can trace this, at least in part, to some of my own experience growing up.
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For a period of my childhood, I lived in a food-insecure household.
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We benefited from food shelf donations,
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and we only ate what my mom could get with her hard work
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on double coupon day at the local supermarket.
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I loved the one day a month I was allowed to buy school lunch.
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Now, I don't know why my parents didn't apply for free school lunch
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or food stamps,
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but the end situation was one where sometimes the refrigerator
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and the cupboards were empty.
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Now, it's been a long time since I have worried about food for myself,
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but that feeling of being hungry is etched deep within me.
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I am driven to do something about hunger.
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And the unusual talent that I bring to the task
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is my deep knowledge of designing and synthesizing nanomaterials
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that can carry molecular cargo
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and transform into specific chemical species.
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Let me stop and give a little bit of background about nanoscience.
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The prefix β€œnano” signifies a billionth,
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so a nanometer is a billionth of a meter.
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In other words, nanoparticles are extremely small.
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You cannot see them with your naked eye or even a high-powered light microscope.
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In fact, you need a specialized instrument
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like the one you see here, called a transmission electron microscope,
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to even see nanoparticles.
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Nanoparticles have actually been around forever.
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You can find naturally occurring nanoparticles in geological formations
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or in the aerosol particles that we breathe.
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But in the last few decades,
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scientists and engineers have gotten very excited about nanomaterials
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because we realized that as you shrink things down to the nanoscale,
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their chemical and physical properties can change drastically.
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For example, a material that's usually unreactive
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when you shrink it down to the nanoscale
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can suddenly catalyze a whole host of chemical reactions.
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Or a material that doesn’t usually conduct electricity, suddenly does.
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As scientists tune the size, shape and chemical composition of a material,
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they can tune those chemical and physical properties.
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Nanoscience gives us a seemingly unlimited palette of accessible chemical
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and physical properties.
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I’m sure you can imagine how useful that can be.
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And scientists have gotten very good
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at knowing exactly how to design nanomaterials
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to have the properties they want.
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We are in a perfect moment to take advantage
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of all of the hard-won knowledge
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that has been systematically gained in laboratories around the world.
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And that’s already happening.
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You can find engineered nanoparticles in a range of products and applications,
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many of which are focused on some of our biggest sustainability challenges.
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Personally, I like to work on the nanomaterials
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that make up the core of lithium-ion batteries for electric vehicles,
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but you'll also find nanomaterials in water filtration technology,
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solar cells and even in clinical applications.
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With all of that background,
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now let me tell you about some of the nanomaterials
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my research group is developing for agricultural applications.
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In some ways, the nanoparticles seem very simple.
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They're made of silica or SiO2 in chemistry language.
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This is the same chemical composition that describes glass or sand.
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And the simple choice was not an accident.
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We wanted to work with Earth-abundant elements,
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and you can't do much better than silicon and oxygen on that front.
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The researchers in my lab are very skilled at designing silica nanoparticles
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with controlled size and surface chemistry.
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We also work hard to control the pore structure,
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because that determines the total surface area,
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as well as the strength of the bonds that hold the nanomaterials together.
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That's because all of those factors are critically important for our end goal,
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which is to get these nanoparticles inside plants,
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either by infiltrating seeds
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or by allowing them to pass through pores on the leaf surface,
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and then, once they're internalized,
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having them transformed to release a molecule
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that the plant can use to protect itself from viruses, fungi or pest attacks.
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In technical terms,
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we want our silica nanoparticles to react with water in the environment
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and dissolve to release a molecule called silicic acid.
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You can think of silicic acid for plants
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like the multivitamin that you take every morning.
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Plants already contain silicic acid,
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they use it to build their cell walls.
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We want to deliver an extra boost of silicic acid,
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with the hypothesis that they'll build stronger cell walls
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and boost their own immune response.
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So now, hopefully you can see the whole picture.
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We design silica nanoparticles with the right size,
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shape and surface chemistry to be taken up into a plant.
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We also design them so that once they're internalized,
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they dissolve to release enough silicic acid
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that the plants live healthier and longer,
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producing more food.
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With all of that background,
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now, let me actually show you some of the nanoparticles that we're making
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and tell you about some of the early,
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exciting results from greenhouse and field studies.
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We've made many variations on the silica nanoparticle theme.
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Here you can see five electron microscope images
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of silica nanoparticles we've made.
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All of them have the same scale bar, that’s just 100 nanometers.
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And all of them are small enough to go into the pores on a leaf’s surface.
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Here you can see some of the silica nanoparticles we’ve designed
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with various pore structures.
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The pore structure ends up being very important
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because the more water can react with the surface of the nanoparticle,
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the better it dissolves and the more silicic acid is released.
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Here you can see some nanoparticles we've designed
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to dissolve at different rates.
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And what you're looking at is a nice, solid nanoparticle at the beginning,
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before it's been exposed to water.
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And then after eight, 16 and 24 hours,
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you can see those nanoparticles hollowing out,
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releasing lots of useful silicic acid.
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With all of these nanoparticles in hand,
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we started working with colleagues
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within the NSF Center for Sustainable Nanotechnology
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to start our first plant studies.
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The initial studies were very simple,
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using watermelon seedlings in a greenhouse.
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Here's the experimental setup.
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We had watermelon seedlings that were going to be planted
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either in healthy soil
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or soil infested with Fusarium, a fungal soil-borne pathogen.
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Before planting them, we dipped them in our silica nanoparticles,
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and then we allowed them to grow in the greenhouse.
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Of course, we also had a parallel set of plants
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that received no nanoparticles, growing in both healthy and diseased soil.
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So the goal was to figure out
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how that single application of silica nanoparticles
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impacted the plants growing in both healthy and diseased soil.
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And the results that we saw were really exciting.
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We found that the plants that were growing in infected soil,
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that had received that one dose of silica nanoparticles
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were 30 to 40 percent healthier than the ones that had not.
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With this exciting result,
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we decided to try some field studies using the same soil conditions
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and the same nanoparticle conditions.
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So we planted watermelon, either in healthy or infected soil,
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and we allowed them to grow for 100 days.
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We tracked the fungal disease,
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and we also measured the amount of fruit that was produced after 100 days.
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And what we found
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is that that one application of one to two milliliters of silica nanoparticles
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way back at the seedling stage,
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led us to a 70 percent increase in watermelon yield.
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Ideally, none of the nanoparticles would end up in the fruit
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that people are going to eat.
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So we analyzed the roots and the above-ground tissue
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and the edible fruit for any sign of silica nanoparticles.
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We saw no increased silicon in the edible watermelon fruit,
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meaning that these nanoparticles did exactly what we designed them to do.
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Given the small amount of nanomaterials
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that we applied to each one of those plants,
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the cost per plant is only about two cents
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or 19 dollars for an acre.
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This is a cost-effective treatment.
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By adding 19 dollar's worth of nanoparticles
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to the average fertilizer cost of 250 dollars,
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a farmer would yield thousands of dollars increase in fruit production.
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With these exciting results in hand,
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we have a lot of other experiments planned and in progress.
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We want to do multiple applications of nanoparticles
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and applications later in the growth process
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to see if that further increases our yield.
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We want to do studies on soybean and wheat,
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critical crops here in the Midwest and around the world.
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Two researchers in my lab recently applied silica nanoparticles
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to potato plants in the field.
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They're going to help harvest and analyze the results this fall.
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I hope that what you see is that this data is really compelling,
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and that nanoparticles have tons of potential to help decrease crop loss.
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And I only told you about silica nanoparticles.
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I can imagine other important chemical compositions
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and even parallel application like remediation of soil pollutants.
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I ask you all to be open-minded about nanotechnology,
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encouraging funding agencies worldwide to invest.
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In the US,
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ask your senators and representatives
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to invest in the National Science Foundation,
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the National Institutes of Health and the US Department of Agriculture
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for both basic and translational research.
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I know farmers are already embracing advanced technology
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in terms of robots and drones and implant sensors.
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I encourage them to embrace this advance as well.
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Now go back to imagining that you're that farmer
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and you've planted enough crops to feed your family for the coming year.
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You do all of the normal things, except this time,
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maybe you use seeds that were infiltrated with silica nanoparticles.
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Or maybe you go through once
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and you spray silica nanoparticles onto your crops.
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As these tiny nanoparticles deliver a big boost of silicic acid
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from the inside,
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your plants overcome disease, and your family is fed.
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Let's use all of the hard work
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that has been done on basic nanotechnology research
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to feed our global family for years to come.
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Thank you.
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(Applause)
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